How to find out lathe speeds [Archive]

surfdabbler

10th May 2014, 11:25 PM

I have an old lathe that is not labelled with speeds. It has 3 speeds, and a back gear for a 2nd three speeds. Anyone got any good ideas for how to find out the speeds? (Short of buying any fancy equipment for measuring lathe speeds.)

Cliff Rogers

10th May 2014, 11:38 PM

Get a digital Tacho, they are less than $14 on ebay. :2tsup:
http://www.ebay.com.au/itm/New-Digital-Laser-Photo-Tachometer-Non-Contact-RPM-Tach-Tester-RPM-Motors-2014-/281303846438?pt=AU_Gadgets&hash=item417f040e26

PLD

10th May 2014, 11:56 PM

I would think there is a mathematical way, based on rpm of motor and size of the different pulleys, But you will have to be much smarter than me to figure it :C. I'd buy the tool mentioned above, it is no more that a calculator you would have to buy to figure it out mathematically.

Mobyturns

11th May 2014, 07:50 AM

http://www.woodworkforums.com/showthread.php?t=181500&highlight=lathe+speed

Cliff Rogers

11th May 2014, 10:18 AM

If you want to have a go at calculating it, go here.

blocklayer is a member here.

http://www.blocklayer.com/pulley-belt.aspx

surfdabbler

11th May 2014, 05:25 PM

Get a digital Tacho, they are less than $14 on ebay. :2tsup:
http://www.ebay.com.au/itm/New-Digital-Laser-Photo-Tachometer-Non-Contact-RPM-Tach-Tester-RPM-Motors-2014-/281303846438?pt=AU_Gadgets&hash=item417f040e26

Aha, thanks for the link. I hadn't realised these things were so cheap! I also hadn't realised the RPM was written on the motor, so I can calculate pulley ratios from there, although I have 2 levels of pulleys to contend with, plus the back gear - could get interesting! Thanks! :)

Cliff Rogers

11th May 2014, 10:02 PM

Test your maths while you wait for the $14 Tacho to arrive. :D

hughie

11th May 2014, 11:05 PM

I have an old lathe that is not labelled with speeds. It has 3 speeds, and a back gear for a 2nd three speeds. Anyone got any good ideas for how to find out the speeds? (Short of buying any fancy equipment for measuring lathe speeds.)

Go here and down load for free, very small file and it works well http://softadvice.informer.com/Download_Rpm_Pulley_Calculator.html

Problem solved you can work out rpms at your leisure